1. Field of the Invention
The present invention relates to a color filter, a light scattering plate, a light scattering adhesive layer, in which a light scattering layer is provided for enlarging visibility angle and for improving display quality, and a liquid crystal display apparatus using at least one of them
2. Description of the Related Art
Liquid crystal display panels have features such as thin form, light weight, low electric power consumption and the like, and are spreading widely as a display instead of CRT (cathode ray tube) and demand thereof is increasing further, recently. Further, these panels are used in various fields, and the commercial trend is directed to a larger screen and higher fineness.
Though liquid crystal display panels have merits such as thin form and driving with lower electric power, light transmission, brightness and viewing angle thereof are insufficient, and particularly, there is an eager desire for improvement in the viewing angle which is significantly narrower as compared with CRT.
In one method for enlarging the viewing angle of a liquid crystal display panel, lights transmitted through the liquid crystal display panel are allowed to scatter to all directions to level lights within the viewing angle. enlarging the viewing angle, and as the method to scatter lights transmitting the panel, a scattering plate is generally used.
As the method for scattering lights by a scattering plate, there are listed a method in which fine particle are dispersed in a scattering plate leading to scattering of lights, a method in which the surface of a scattering plate is roughened to cause scattering of lights, a method in which a grating-like fine structure is formed on the surface of a scattering plate leading to scattering of lights, as well as other methods, and among them, a method In which lights are scattered by fine particles dispersed in a scattering plate is most frequently used.
As the method for integrating a scattering layer into a liquid crystal panel, there are suggested a method in which a light scattering film is pasted on the surface of a liquid crystal panel, a method in which a light scattering adhesive having light scattering function is used as an adhesive in pasting a polarizing plate, a method in which a light scattering layer produced by dispersing fine particles in a resin is formed on a color filter, and the like, and some of them are disclosed. For example, JP-A No. 10-206837 discloses a method in which a light scattering layer produced by dispersing a transparent pigment of high refractive index such as cerium oxide and the like having an average particle diameter of 0.4 xcexcm to 4 xcexcm and a refractive index of over 1.8 in a resin is placed on the observation substrate side.
Further, JP-A No. 7-218705 discloses a light scattering film in which an acrylic fine particle having an average particle diameter of 1 xcexcm to 50 xcexcm is dispersed
The object of the present invention is to provide a light scattering layer in which the dispersibility of a fine particle in a transparent resin as a matrix is large and forward scattering property is improved and light transmittance is excellent, and to provide a color filter, a light scattering plate, a light scattering adhesive layer, in which scattering property is improved while maintaining high transmittance of lights, and a liquid crystal display using at least one of them.
The present inventors have intensively studied for solving the above-mentioned problems, and resultantly, found that a light scattering layer in which forward scattering property is improved and light transmittance is excellent can be formed by using a specific fine particle as a scattering material, leading to completion of the present invention.
Namely, the present invention provides the following (1) to (6) aspects.
(1) A light scattering resin layer providing scattering of a transmitted light by dispersion of an inorganic fine particle in a transparent resin, wherein the above-mentioned fine particle is a polyhedral particle having, substantially no fractured surface, L/S ratio is 2 0 or less when the major axis length is represented by L and the minor axis length is represented by S, the number-average particle diameter of the above-mentioned fine particle is 0.1 xcexcm or more and 20.0 xcexcm or less, and the particle size distribution in terms of D90/D10 value is 7 or less when particle diameters at 10% cumulation and 90% cumulation from smaller particle side of cumulative particle size distribution are represented by D10 and D90, respectively.
(2) A color filter for a liquid crystal display, wherein the light scattering resin layer of (1) is provided on one surface or both surfaces of a transparent substrate or on a color filter layer.
(3) A liquid crystal display, wherein the color filter for a liquid crystal display of (2) is contained as a constituent element.
(4) A light scattering plate, wherein the light scattering resin layer of (1) is used on the surface of or in a scattering plate.
(5) A light scattering adhesive layer, wherein light scattering function is imparted to an adhesive layer by using a resin having adhesion as the above-mentioned transparent resin in the light scattering resin layer of (1).
(6) A liquid crystal display, wherein the light scattering plate of (4) or (5) is equipped on at least one side either of the outer side or the inner side of a liquid crystal cell.